Formation of the ends of tubes for drawing purposes.



H. HIGGIN. FORMATION OF THE ENDS 0F TUBES FOR DRAWING PURPOSES.

APPLIOATIOR FILED JAN.30, 1911.

Patented July 2, 1912.

HENRY HIGGIN, OF NEWPORT, KENTUCKY, ASSIGNOR TO HIGGIN' MANUFACTURING COMPANY, OF NEWPORT, KENTUCKY, A CORPORATION OF WEST VIRGINIA.

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FORMATION OF THE ENDS OF TUBESFOR DRAWING PURPOSES.

Specification of Letters Patent.

Patented July 2, 1912.

Application filed January 30, 1911. Serial No. 605,525. a

To all whom it may concern:

Be it known that I, HENRY HreelN, a citizen of the United States, and a resident of the city of Newport, in the county of Campbell and State of Kentucky, have invented certain new and useful Improvements in the Formation of the Ends of Tubes for Drawing Purposes, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to that certain novel construction or formation of the end of tubes to be hereinafter particularly pointed out and claimed, whereby such tubes shall be contracted at the end to provide an effectual grip for the gripping device, by means of which in the process of manufacture the tube is forcibly drawn through a suitable die to reduce the tube to the proper diameter, thickness of material, and smoothness of finish.

The object of the invention is to contract the end of the tube so that a minimum amount of the tube shall be used for the grippers at the same time that the contraction is uniform, and provision is made for the reception of a plug within the contracted end to support the gripping device, whereby the draft of the gripping'device may be applied in the direct line of the axis of the tube, and in which the contraction is so arranged that for subsequent drawing of the tube the gripping end may be uniformly contracted into substantially a solid section.

In the drawings,Figure 1 is a perspec' tive View of the end portion of a tube illustrating the first operation in the process of contracting. Fig. 2 is a similar perspective view with the end of the tube contracted for the gripping device. Fig. 3 is a side elevation of same with the gripping plug inserted in the end of the tube. Fig. 4t is a perspective View of the plug. Fig. 5 is a perspective view of the end of the tube showing how it may be contracted into a substantially solid form for subsequent drawings.

It will be understood that the process of forming seamless metal tubes consists in drawing the tube lengthwise through a metal ring or die of the desired diameter, and that, in order to draw the tube through such a die, it is necessary to provide a solid and substantial contracted portion for the gripping device to prevent slippage under the powerful strains to which the tube is subjected in being forcibly drawn through the die. In thus contracting the end of the tube, a simple method would be to merely hammer down the end of the tube to afford a proper gripping for the grippers. lVith this method, however, the gripping device does not take hold of the end of the tube in the exact line of the axis of the tube, so that the strain on the tube is very apt to come out of alinement, and the tendency is to draw the tube unevenly. Then, again, if care is taken in hammering down the end of the tube by uniform blows so that the pointed end shall attend proper alinement for the grippers, too abrupt a shoulder is apt to result, which presents diiliculties in starting the tube through the die. It is of advantage, therefore, that the contraction of the tube shall be uniform, and that space shall be left within the tube for the insertion of a solid metal plug to serve as a backing. Then, again, in the ordinary process of pointing the tube for the gripping device, in order to prevent slippage, a considerable portion of the tube has been hammered down, and this involves a waste of material which adds very appreciably to the cost of the manufacture of such drawn tubing. In my improved construction all these difliculties are obviated.

1 represents the body of the tube, and in order to eifectively and uniformly contract the end, the tubing is subjected to two op erations. By means of suitable dies, which do not need to be illustrated, in the first operation the tube is initially contracted as shown at 2 in Fig. 1. About half of the cylindrical surface of the tube, one quarter on each side as at 3, 4, is by this preliminary treatment only changed in form very slightly, while for the other two opposite quarters of the tubing the tube is formed with the corrugations 5, 6. Then, by a sec ond set of dies, the inner folds 8, 9 on one side, and 10, 11 on the other are compressed into the condition shown in Fig. 2, leaving the cylindrical portions 12, 13 with opened folds 1 1, 15 opposite each other, and closed folds 16, 17 on one side and 18, 19 on the other. The tube is then ready for drawing, only a very few inches of the tube have to be thus contracted. A gradual sloping shoulder 20 is formed with the body of the tube and ample space is provided for the insertion of the solid metal plug 21, so that Copies of this patent may be obtained for a perfectly solid unyielding end is provided for the tube upon which the grippers can take a firm grasp Withoutany liability of slipping. The plug 21 is preferably pro vided with a hole 22, by means of which the plug can be withdrawn from the end of the tube at the end of the process, a wire being usually looped through the opening.

When the tubing is to be still further drawn, with the above described construction the end can be still further contracted into substantially a solid condition. Inasmuch as the folds 14:, 15 are open and the loops 16, 17 on one side and 18, 19 on the other are closed, when the end of the tube is subjected to smaller dies to fully contract same, the cylindrical portions of the tube are substantially brought together as shown at 23, 24 in Fig. 5, the folds 14, 15 open out and are brought into substantial contact with each other as shown at 25 in Fig. 5, and a substantially solid end for the tube is provided without waste of material and with the axis of the solid contracted end in alinement with the axis of the tube.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A cylindrical tube, adapted to be drawn, and having a body portion, and a contracted end portion of uniform diameter throughout, symmetrical in cross section, the end portion being provided with opposite corrugations to form an open fold on opposite sides with closed folds on either side of each open fold and with semi-cylindrical portions intermediate the corrugations adapted to be brought together to form a solid end for the tube, substantially shown and described.

2. A cylindrical tube, adapted to be drawn, and having a body portion, and a contracted end portion of uniform diameter throughout, symmetrical in cross section, the end portion being provided with opposite corrugations to form an open fold on opposite sides with closed folds on either side of each open fold, and with semicylindrical portions intermediate the corrugations, with an opening through the end portion in line with the opening in the tube adapted to receive a metal plug to support external pressure on the contracted portion with the semicylindrical portions adapted to be brought together to form a solid end when the plug is removed, substantially as shown and described.

HENRY HIGGIN.

Attest HENRY A. FABER, CONRAD GUENTHER.

five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

